Combustion Device Transient Pulsation Control via Inert Fluid
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Solution Overview
Problem
Combustion pulsations during transient operations in gas turbines cause mechanical and thermal stress due to fluctuating pressure waves, which affect fuel injection and lead to reduced fuel mass flow, necessitating a method to counteract these pulsations.
Innovation Solution
A method that involves supplying an additional inert fluid during transient operations, such as startup or fuel switchovers, to stabilize fuel injection by regulating parameters like fuel mass flow and differential pressure, ensuring they remain above critical values or within specific ranges to prevent pulsations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If fuel mass flow is reduced during transient operation, then fuel economy is improved, but combustion pulsations increase due to fluctuating pressure waves affecting fuel injection
Solution Approach 1:
An additional fluid supply device is introduced as an intermediary system between the fuel supply and combustion chamber. This mediator supplies an additional fluid (inert gas or vapor) that stabilizes the combustion process by compensating for pressure wave effects, allowing reduced fuel flow while maintaining combustion stability.
Solution Approach 2:
The system changes the parameters of the combustion environment by introducing an additional fluid that modifies the pressure and flow characteristics within the combustion device. This parameter change stabilizes the combustion process during transient operation, preventing pulsations even when fuel mass flow is reduced.
2Loss of energy
If fuel mass flow is reduced below critical value, then energy loss is improved, but fuel injection becomes unstable due to pressure waves alternatively promoting and hindering injection
Solution Approach 1:
The additional fluid supply acts as a buffer that smooths out pressure fluctuations affecting fuel injection. By introducing this intermediary fluid, the system maintains reliable fuel injection even when operating below critical fuel mass flow conditions.
Solution Approach 2:
The additional fluid supply provides beforehand cushioning by pre-stabilizing the combustion environment before pressure waves can cause injection instability. This protective measure ensures fuel injection reliability is maintained during transient operations.
3Stability of the object's composition
If additional fluid is supplied to stabilize fuel injection, then combustion pulsations are reduced, but device complexity increases
Solution Approach 1:
The additional fluid supply device is designed with multi-functionality, serving both as a stabilizer for combustion pulsations and as a control mechanism for fuel injection. This universal approach reduces the need for separate dedicated systems, thereby limiting the increase in device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively reduces combustion pulsations by maintaining stable fuel injection, thereby minimizing mechanical and thermal stress on the combustion device and downstream turbine components.
Implementation Method 1
During transient operations pressure waves can generate within the combustion device... the fluctuating pressure within the combustion device alternatively promotes and hinders fuel injection
Implementation Method 2
during at least a part of a transient operation such as for example a start up, a switch off or a switch over, an additional fluid is supplied together with the fuel
Implementation Method 3
During operation the fuel and the oxidiser react within the combustion device and generate high pressure and temperature flue gases that are expanded in a turbine
Data Source
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AI summary
The method for operating a combustion device (5, 15, 25) includes supplying a fuel (35) and an oxidiser (36) into the combustion device (5, 15, 25) and burning them. According to the method, during at least a part of a transient operation, an additional fluid (37) is supplied together with the fuel (35), and its amount is regulated to counteract combustion pulsations.